nonstress test
Pronunciation: non-STRESS
Also written as: NST
Antepartum fetal surveillance test that monitors fetal heart rate response to spontaneous fetal movements.
Full Definition
The nonstress test (NST) is a noninvasive method of antepartum fetal surveillance that assesses fetal well-being by monitoring the fetal heart rate response to fetal movements. A reactive NST shows at least two fetal heart rate accelerations of 15 beats per minute above baseline, lasting 15 seconds, within a 20-minute period. This test is commonly used in high-risk pregnancies to evaluate placental function and fetal oxygenation status without inducing uterine stress through contractions.
Usage
Usage note: Commonly abbreviated as NST; reactive result is reassuring, nonreactive requires further evaluation.
In Context
- "The nonstress test was reactive with good baseline variability and appropriate accelerations." — Antepartum surveillance report
- "Due to gestational diabetes, twice-weekly nonstress testing was initiated at 32 weeks." — High-risk pregnancy management plan